The long-term goal of this research program is to understand the organization features of the prefrontal limbic cortices which underlie their role in integrative cognitive, mnemonic, emotional and autonomic processes. Work conducted during the previous funded period suggests that the prefrontal limbic cortices in the rhesus monkey have a pivotal role in the connectional and functional organization of prefrontal cortices, in general. The proposed studies draw upon the unique connections of prefrontal limbic cortices to address the structural basis of their role in autonomic functions. Prefrontal limbic cortices have a unique set of connections with structures associated with emotions, and may be an essential link for those autonomic responses that are triggered by emotions. The goal of this project is to test this hypothesis by investigating critical pathways through which prefrontal limbic cortices can change autonomic responses triggered by emotions. Neural tracing studies will be conducted to investigate whether prefrontal limbic cortices that receive input from structures associated with emotions project to hypothalamic and brainstem autonomic nuclei and thereby innervate and affect directly peripheral autonomic organs, including the heart and the lungs. Multiple pathways will be labeled simultaneously with the aid of anterograde and retrograde tracers and mapped. A series of architectonic, histochemical, immunocytochemical and molecular markers will be used to delineate hypothalamic nuclei to determine whether they belong to a group which have autonomic functions. The proposed studies have implications for understanding the link between strong emotions and cardiovascular disorders, and will build upon a foundation to investigate the selective vulnerability of prefrontal limbic cortices in neurologic and psychiatric diseases.